Abstract: Methods and apparatus for compressing data for network transport in support of continuous availability of applications are described. One computer-implemented method of compressing data includes receiving a current instance of data in an input buffer. A candidate chunk of data is selected from the input buffer. A signature hash is computed from a signature length range of data within the candidate chunk. A matching dictionary entry having a matching signature hash from a multi-tiered dictionary is identified. The matching dictionary entry prospectively identifies a location of a prior occurrence of a selected range of consecutive symbols including the signature length range of data within at least one of the current instance of data and a prior instance of data in the input buffer. A dedupe processed representation of the instance of data is formed wherein a dedupe item is substituted for the selected range of consecutive symbols if the selected range is verified as recurring.

Abstract: Methods and apparatus for compressing data for network transport in support of continuous availability of applications are described. One computer-implemented method of compressing data includes receiving a current instance of data in an input buffer. A candidate chunk of data is selected from the input buffer. A signature hash is computed from a signature length range of data within the candidate chunk. A matching dictionary entry having a matching signature hash from a multi-tiered dictionary is identified. The matching dictionary entry prospectively identifies a location of a prior occurrence of a selected range of consecutive symbols including the signature length range of data within at least one of the current instance of data and a prior instance of data in the input buffer. A dedupe processed representation of the instance of data is formed wherein a dedupe item is substituted for the selected range of consecutive symbols if the selected range is verified as recurring.

Abstract: Recovery systems and methods for sustaining the operation of a plurality of networked computers (20a,20b) in the event of a fault conditions are described. The basic recovery system comprises a plurality of virtual machines (31a,31b) installed on a recovery computer (30), each virtual machine being arranged to emulate a corresponding networked computer, and the recovery computer being arranged, in the event of a detected failure of one of the networked computers, to activate and use the virtual machine which corresponds to the failed networked computer (20). The recovery computer (30) may be located on the same network (12) as the networked computers (20), or alternatively on a remotely located local network in case of failure of the entire local network (12).

Abstract: Recovery systems and methods for sustaining the operation of a plurality of networked computers (20a,20b) in the event of a fault conditions are described. The basic recovery system comprises a plurality of virtual machines (31a,31b) installed on a recovery computer (30), each virtual machine being arranged to emulate a corresponding networked computer, and the recovery computer being arranged, in the event of a detected failure of one of the networked computers, to activate and use the virtual machine which corresponds to the failed networked computer (20). The recovery computer (30) may be located on the same network (12) as the networked computers (20), or alternatively on a remotely located local network in case of failure of the entire local network (12).

Abstract: Recovery systems and methods for sustaining the operation of a plurality of networked computers (20a, 20b) in the event of a fault conditions are described. The basic recovery system comprises a plurality of virtual machines (31a, 31b) installed on a recovery computer (30), each virtual machine being arranged to emulate a corresponding networked computer, and the recovery computer being arranged, in the event of a detected failure of one of the networked computers, to activate and use the virtual machine which corresponds to the failed networked computer (20). The recovery computer (30) may be located on the same network (12) as the networked computers (20), or alternatively on a remotely located local network in case of failure of the entire local network (12).

Abstract: Recovery systems and methods for sustaining the operation of a plurality of networked computers (20a, 20b) in the event of a fault conditions are described. The basic recovery system comprises a plurality of virtual machines (31a, 31b) installed on a recovery computer (30), each virtual machine being arranged to emulate a corresponding networked computer, and the recovery computer being arranged, in the event of a detected failure of one of the networked computers, to activate and use the virtual machine which corresponds to the failed networked computer (20). The recovery computer (30) may be located on the same network (12) as the networked computers (20), or alternatively on a remotely located local network in case of failure of the entire local network (12).

Abstract: A system for compressing and decompressing sequential records to store only those parts of a record which differ from the previous record. The system for compressing includes a bit map which indicates which parts of a record if any are the same as the preceding record. The system enables compression and decompression of records without the need to access additional blocks and perform additional disk I/Os to obtain the expanded version of a given compressed record.

Abstract: First and second data processing systems located at first and second sites are configured with the first data processing system having a primary memory unit at the first site and a mirror memory unit at the second site with the first and second sites coupled by a single-mode optical fiber. Fiber optic switches at the first and second sites can be reconfigured to coupled the mirror disc to the second data processing system with minimal delay.